Divisions of nervous system

Part 2

Spinal Cord Functions:

Centre for many reflex actions Provides a means of

communication between brain and the spinal nerves which leave the spinal cord

Spinal cord structure Contains interneurons Axons of sensory neurons Dendrites of motor neurons Contains both myelinated and

unmyelinated nerve fibres (white and grey matter)

The Brain Conscious brain: cerebrum –

forebrain Responsible for speech, reasoning,

memory and personality Divided into 2 hemispheres: right

and left Each half contains 4 lobes

Frontal lobe Motor control of skeletal muscles Concentration, problem solving,

judgement

Parietal Sensory recognition of

temperature, touch, pain from body surface

Understanding of language Using speech

Temporal Sensory recognition of smell and

hearing Memory of visual scenes, music,

etc.

Occipital Sensory area for sight Combining visual images with past

experiences

Two side of brain The two sides of the brain control motor

functions for opposite sides of the body (ie. Right hemisphere controls left side of body)

Evidenced by people who have had strokes

Both sides are connected by the corpus callosum

Cutting corpus callosum can control seizures in epileptics but lose left-right control

Unconscious brain: everything below cerebrum

Thalamus: Highest part of brain before

cerebrum Receives sensory input from all

parts of the body (except smell) Sorts out incoming stimuli and

sends then to the brain (appropriate regions of)

“gatekeeper”

Hypothalamus Below thalamus Important for homeostasis Controls hunger, sleep, thirst, etc. Controls pituitary gland Neuroendocrine control centre Body temperature Regulates autonomic nervous system

Cerebellum Second largest portion of brain Coordinates muscle movements Maintains balance with help from

inner ear Maintains muscle tone posture

Pons Relay station that passes info

between cerebellum and medulla oblongota

Medulla oblongota Closest to spinal cord Controls heartbeat, breathing and

vasoconstriction (blood pressure) Reflex controls for vomiting,

coughing, sneezing and swallowing Also regulates autonomic NS